Supreme Court Justice Ruth Bader Ginsburg … told The New York Times that, despite calls from some on the let for her to retire before President Barack Obama leaves office so he can name a liberal replacement, she intends to stay on the court “as long as I can do the job full steam, and that, at my age, is not predictable.” Appointed by former President Bill Clinton in 1993, Ginsburg has survived cancer twice.

She also opened up the current court under Chief Justice John Roberts, who led the majority in striking down a crucial part of the 1965 Voting Rights Act in June. Ginsburg said “if it’s measured in terms of readiness to overturn legislation, this is one of the most activist courts in history.”

In a fiery dissent, Ginsburg blasted the court’s voting rights decision, saying it could “hardly be described as an exemplar of restrained and moderate decision making.”

Justice Ginsberg certainly has a point about the Court’s decision in Shelby County v. Holder, No. 12-96 (slip op. June 25, 2013) (.pdf), which struck down Section 4 of the federal Voting Rights Act, the provision that required nine southern states and a handful of municipalities outside the South to obtain the federal government’s approval before implementing changes to their election laws. In his opinion for the majority, the Chief Justice essentially substituted his own judgment for that of Congress, determining that there no longer was a sufficient reason to treat certain states and certain municipalities differently from the rest of the country for purposes of ensuring the voting rights of minorities.

The Voting Rights Act case was a particularly odd example of conservative judicial activism, given that the Fifteenth Amendment, which provides that “[t]he right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude,” also states:

The Congress shall have power to enforce this article by appropriate legislation.

U.S. Const., Amend. XV, § 2.

In other words, it’s for Congress, not the Court, to determine the appropriate means of enforcing the Fifteenth Amendment’s objective. But in Shelby County, the Roberts Court determined that it knew better than Congress, and so it rejected the means Congress had chosen. That’s the essence of judicial activism: striking down otherwise proper laws because the Court doesn’t like Congress’ policy choices.

But it’s not the first time Justice Roberts engaged in a little judicial sleight-of-hand to override congressional authority. In the Court’s famous (or infamous) opinion in National Federation of Independent Business v. Sebelius, No. 11-393 (slip op. June 28, 2012) (.pdf), which upheld the Affordable Care Act’s individual insurance mandate under the Tax Clause of Article I, Justice Roberts first found that Congress lacked the authority to impose the individual mandate under Article I’s Commerce and Necessary and Proper Clauses. To reach that conclusion, Justice Roberts had to draw a somewhat bizarre distinction between Congress’ power to regulate “activity” versus “inactivity” under the Commerce Clause:

As expansive as our cases construing the scope of the commerce power have been, they all have one thing in common: They uniformly describe the power as reaching “activity.” It is nearly impossible to avoid the word when quoting them. …

The individual mandate, however, does not regulate existing commercial activity. It instead compels individuals to become active in commerce by purchasing a product, on the ground that their failure to do so affects interstate commerce. Construing the Commerce Clause to permit Congress to regulate individuals precisely because they are doing nothing would open a new and potentially vast domain to congressional authority.

National Federation of Independent Business, slip op. at 19-20.

You’ll note, of course, that the Commerce Clause itself makes no distinction between “activity” and “inactivity”:

The Congress shall have Power …

To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes …

And the Necessary and Proper Clause further provides that Congress can “make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers,” including the commerce power. Id. Which, you’d think, means that it’s up to Congress to determine whether it’s appropriate, in a given circumstance, to regulate “inactivity,” where that “inactivity” affects interstate commerce. Justice Roberts, however, saw the ACA case as an opportunity to impose a heretofore unknown restriction on the commerce power, and thus the activity-vs.-inactivity rule was born.

So, yeah, Justice Ginsberg has a point: Justice Roberts seems to have no problem substitution his own judgment for Congress’ judgment, at least in those instances where Congress is actually trying to help people.